The back, for example of a tufted carpet, must serve primarily for firmly holding the pile fibers, since in tufting the pile fibers are placed in the primary carrier but can be pulled out easily once again. The back of the carpet must also provide a greater volume, a soft step, and good installation ability with dimensional stability. It is known that these conditions can be produced with a precoat made of latex which must cure. As the second coat, a jute cloth could then be applied. The second layer should also consist of a foam that must be vulcanized. These manufacturing methods are very costly and the product thus produced is environmentally hazardous when disposed of later.
The goal of the invention is to find a method with which the environmentally hazardous binder, foam, and required chemicals can be avoided. At the same time, the pile goods product, especially a carpet manufacturing system, must become cheaper and yet the pile goods must have all the necessary qualities.
To achieve this goal, provision is made such that preferably a nonwoven is fastened by hydrodynamic water needling to the back of a primary carrier that holds the pile fibers. It has been found that in water needling the fibers of the stabilizing nonwoven can be shot into the back of the primary carrier and into the pile fibers held there far enough that parts of the nonwoven that have a stabilizing effect are visible on the exterior of the pile, or on the roots of the pile of the web goods. The nonwoven is needled only with the pile fibers visible on the back side and reversed there and with the back of the primary carrier so that the pile fibers are stabilized in the back.
It is true that in practice a more stable and possibly also a more voluminous carpet is desirable than one that has only a lightweight nonwoven on the back. It is therefore advantageous in designing the method if a composite made of a lightweight nonwoven, a coarsely braided, dimensionally stable stability area element, and possibly also a lightweight nonwoven are combined and laid on the non-solidified back of the carpet and then connected in one work step with the back of the carpet using hydrodynamic water needling. Now the carpet has not only a solidified pile permanently held in the back but also the desired volume and, with the stability area element, the required dimensional stability as well. Such a stabilizing back layer can weigh up to 600 g/m2.
Using the method according to the invention, a pile carpet with the desired quality properties can be manufactured more economically, one that has no chemicals relative to the design of the back so that recycling no longer poses any problems.
As a nonwoven for stabilizing the pile fibers, a carded nonwoven should be used which can be done without solidification and possibly also slight pre-solidification using water needling, and placed on the back of the primary carrier. Polyester, PP, PA, or other fibers can be used as the fibers. The nonwoven can have its thickness and weight adapted to the specific requirements and it should preferably have a weight of 100-200 g/m2. Then this web material should pass beneath the beam of a water needling machine with the water pressure adjusted so that the fibers of the nonwoven are woven once, in other words the nonwoven or the composite acquires greater strength, but at the same time its fibers penetrate into the pile fibers bent in the back of the web goods and penetrate the primary carrier so that the pile web goods are stabilized without the pile being changed in any way. The water pressure must be adapted to the individual conditions. Pressures up to 600 bars can be used.